Return-Path: Received: from mtain-md07.r1000.mx.aol.com (mtain-md07.r1000.mx.aol.com [172.29.96.91]) by air-ma09.mail.aol.com (v129.4) with ESMTP id MAILINMA092-b5354cc75271e7; Tue, 26 Oct 2010 18:13:05 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-md07.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7F69538000151; Tue, 26 Oct 2010 18:13:01 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PArjx-0008Gw-Rq for rs_out_1@blacksheep.org; Tue, 26 Oct 2010 23:11:33 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PArjx-0008Gn-Aw for rsgb_lf_group@blacksheep.org; Tue, 26 Oct 2010 23:11:33 +0100 Received: from mail-bw0-f43.google.com ([209.85.214.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PArjv-0007Gc-2K for rsgb_lf_group@blacksheep.org; Tue, 26 Oct 2010 23:11:33 +0100 Received: by bwz1 with SMTP id 1so14776bwz.16 for ; Tue, 26 Oct 2010 15:11:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=XmvY4uTYgLbNZ6I75LMnDx3nWWtDuACEbNxJRCpUYok=; b=ebJUrajFADjvnGGgiOU3xoq+eL9B2caXKqTL1MQQx+b02fVcc1U+6NyjkxeDo9o5Yk PxAjbXj1GxjS3pZA4mLBaGMkSO8ZwJKDT8lyCDLKQ4KQXXnY/NHj0kZNnmL3CdndHPDv KDJrE1+BkMkgnfMXFaA62I+tgQgZwcRhs+m2A= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=k9DhtdMF50R7CNUX++5AjQwTWQ0duBfA9A1Oof2aj6EPtTj1g882RE42IrPr1liDo8 6G99fjgfOYIXEk+zT8GBg4LKu+84VYGPwExLjZbkm6RBEoFRExR/Xpe5YK9FXHiVJsEn Wepg0AvTPuCPzCDlZiC6MMnBksavEvNAQc354= MIME-Version: 1.0 Received: by 10.204.99.68 with SMTP id t4mr6431532bkn.40.1288131089959; Tue, 26 Oct 2010 15:11:29 -0700 (PDT) Received: by 10.204.23.10 with HTTP; Tue, 26 Oct 2010 15:11:29 -0700 (PDT) In-Reply-To: <4CC74C5E.9030203@iup.uni-heidelberg.de> References: <4CC74304.3090903@iup.uni-heidelberg.de> <4CC74C5E.9030203@iup.uni-heidelberg.de> Date: Tue, 26 Oct 2010 23:11:29 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: VLF: whistler duct AMATEUR propagation Content-Type: multipart/alternative; boundary=001485f7bf580a8ab804938c647a X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-sid: 3039ac1d605b4cc7526d0744 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --001485f7bf580a8ab804938c647a Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Stefan, If I remember correctly, you have to visualise the magnetic field lines going from a point in the northern hemisphere to the southern hemisphere at the conjugate point i.e. as far south as north of the magnetic equator. Signals will only be received close to this point at any strength by propagation along the magnetic field lines in whistler duct mode. With whistlers, triggered by a strong lightning impulse, the signal can propagate back and forth between N/S hemispheres being more frequency dispersed with each pass. The sound is amazing. Helliwell's book shows one strong series of audio frequency echoes lasting over a minute in the sunsp= ot maximum of the late 1950s, but this is rare. With amateur signals we would be lucky to get from Europe to Southern Africa once before signals became too weak to detect. Who would have even believed that such experiments by amateurs would be seriously considered, even 12 months ago? You and others working on this= are *true* pioneers and you all deserve great credit for this. I am only "dabbling at the edges" and have a *great* deal to learn. 73s Roger G3XBM 2010/10/26 Stefan Sch=E4fer > Hi Roger, > > Am 26.10.2010 23:18, schrieb Roger Lapthorn: > >> Stefan, >> >> The possibility of whistler duct AMATEUR propagation is fascinating. Th= ere >> are (I think) spectrograms of such propagation from NAA (~14kHz) back= in the >> 1965 book "Whistlers and Related Ionospheric Phenomena" by J.A.Hellliwe= ll (I >> have a copy). This could mean signals getting to, for example, conjugat= e >> locations in the southern hemisphere (S.Africa?) with relatively low >> attenuation. A chirped signal would also show whisper dispersion I gues= s. >> > Yes, absolutely interesting! We will do that! And SpecLab can easily > generate such a signal, my PA can easily transmit such a signal and my= earth > antenna can easily radiate such a (broad band) signal! :-) > > Any further hints/ideas, Roger (and the group)? > >> >> You will need some grabbers in distant places! >> > Maybe ZL2AFP can help us here by receiving? :-) > > 73, Stefan > > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm G3XBM GQRP 1678 ISWL G11088 --001485f7bf580a8ab804938c647a Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Hi Stefan,

If I remember correctly, you have to visualise the magne= tic field lines going from a point in the=A0 northern hemisphere=A0 to the= southern hemisphere at the conjugate point i.e. as far south as north of= the magnetic equator. Signals will only be received close to this point= at any strength by propagation along the magnetic field lines in whistler= duct mode.

With whistlers, triggered by a strong lightning impulse, the signal ca= n propagate back and forth between N/S hemispheres being more frequency di= spersed with each pass. The sound is amazing. Helliwell's book shows= one strong series of audio frequency echoes lasting over a minute in the= sunspot maximum of the late 1950s, but this is rare. With amateur signals= we would be lucky to get from Europe to Southern Africa once before signa= ls became too weak to detect.

Who would have even believed that such experiments by amateurs would= be seriously considered, even 12 months ago? You and others working on th= is are true pioneers and you all deserve great credit for this. I= am only "dabbling at the edges" and have a great deal to= learn.

73s
Roger G3XBM


2010/10/26 St= efan Sch=E4fer <schaefer@iup.uni-heidelberg.de>
Hi Roger,

Am 26.10.2010 23:18, schrieb Roger Lapthorn:
Stefan,

The possibility of whistler duct AMATEUR propagation is fascinating. There= are (I think) spectrograms of such propagation from NAA (~14kHz) back in= the 1965 book "Whistlers and Related Ionospheric Phenomena" by= J.A.Hellliwell (I have a copy). This could mean signals getting to, for= example, conjugate locations in the southern hemisphere (S.Africa?) with= relatively low attenuation. A chirped signal would also show whisper disp= ersion I guess.
Yes, absolutely interesting! We will do that! And SpecLab can easily gener= ate such a signal, my PA can easily transmit such a signal and my earth an= tenna can easily radiate such a (broad band) signal! :-)

Any further hints/ideas, Roger (and the group)?

You will need some grabbers in distant places!
Maybe ZL2AFP can help us here by receiving? :-)

73, Stefan




--
http://g3xbm-qrp.blogspot.com/<= br>http://www.g3xbm.c= o.uk
http://www= .youtube.com/user/g3xbm
G3XBM=A0=A0 GQRP 1678=A0=A0=A0 ISWL G11088<= br> --001485f7bf580a8ab804938c647a--